Ore roasting furnace



June 7, 1960 P. GATES om: RoAsTING FuRNAcE iled July 15. 1957' 3 Sheets-Sheet l Pm/L @9155,

Ivrea/rae.

June 7,4960 I P. GATES 2,939,695

ORE ROASTING FURNACE Filed July l5, 1957 3 Sheets-Sheet 2 Pm/L. @n res,

Irfan/59s June 7, 1960 P. GATES ORE RoAsTING FURNACE 3 Sheets--SheerI 3 Filed July 15, 1957 i z,sys9,s95 r o oRE RoAsTlNr;Y FURNACE I APaul Gates, 2675 Fashion ve., [long Beach, Calif.

` Filed my 1511951, ser, 10.672,033 Y somme VY(ci. 2661-10) Y culties due to the `volatile nature of the mercuryfand its chemical characteristics` whenv in theivapor-state. YIn the stateof the art prior to 'the present invention, adequate `control of the atmosphere in-which the mercury ore is being heatedhas Ynotnbeen YpossibleV in anyk apparatus flitfw 1Y States, Para 0 latented June 7, 1960 ice b y the addition of 'controlled' amounts of air or other gases. f

Yet another object of the present invention is to pro A vide an ore roasting furnace in which the volatile constituents of the ore are driven oii in a gaseous condition and condensedand recovered while in a controlled atmospheric condition. l Y

VA still further object of the vpresent invention is to provide an ore roasting furnace in which a stream of ore is introduced 'to thev furnaceand conducted'through the furnace while being heated and Vagitated tojca'u'se its volatile constituents to be liberated. 1

Yet another'object of the presentV invention is to provide an ore roasting furnace having ahigh degree of heating and mechanical eiiiciency withA a minimumlof parts which are subjected to abrasive wear and containing no moving parts within the furnace chamber. n

-A furnace in accordance with thepresent invention comprises a shell defining a furnace heating chamber with a plurality of ore carrying decks upon'which the ore is moved from an ore inlet to an ore residue outlet along va tortuous agitated path. Means are provided for imparting an oscillatory movement to the ore` carrying decks while a source of heat heats the ore to extract volatile materialsduring the tortuous movement. Ore inlet means andere residue outlet vmeans are provided v .which allow the charging of ore and extraction ofore which furnishes V a continuous cycle ofore` treatment and extraction. That is, if ore is charged to,and the mercury and residue removed from --the"furnace, while the furnace is in operation,` the yatmosphere within the extraction furnace is substantialy open since the ingress yof air will occur during'any continuous charging'operation heretofore known to the art. L`VAlso .the continuouslyV i charged furnaces ofthe priorVartV have been ineicient with respect tothe heat' input "required since the large volume of air which is introduced into the Vfurnace must be heated and is subsequently exhausted with a high heat 'charging and extraction of ore from the furnace during operation of'the furnacefwhile controlling `the latrnos- `sphere'within the furnace.l t Y Itis another object ofthe present invention to provide Yan improved rore furnace which is compact, but provides an extensive orel heating surface while 'requiringa Y sub stantially smaller heat input than ore wastingfurnaces heretoforeknown tothe art.1v v :.5 t Y It is'another object ofthe present videanV ore` roasting furnace which subjects the ore-withinthe furnace toan eicientlheating cycle.

YIt is a: further objectof-the'fpresent inventionto provide an .ore charging apparatus by means of which ore can be'fed to a; furnace heating .chamber` during operation of the furnacewithouta resulting ingress of air to the chamber. f Y Y .v x

A further object of the present invention is to provide an ore roastingvchamber whichfcauses agitated flow of ore through the furnace chamber. v

A still further object of the present invention is to A provide an ore roasting furnace in which a controlled atmosphere can bemantaincd in the heating chamber invention to pro-v Aloss. Heating ineiciency is'also caused when a large Iresidue during operation of the furnace without the inallow control of the atmosphere within the chamberil The novel features which are believed to be characteristic of the invention both as to its organization and method of operation together withfurther objects and advantages thereof will be better understood from the Yfollowing description considered inl connection with the accompanying drawing in which the invention isy illustrated by way of example. It is to be expressly understood, however, that the drawing is for the purpose of illustration and descriptionfonly and is -not intended as a definition of the limits of the invention.

Figure l isf a view in elevation and partly in section of a presently preferred embodiment of this invention as applied to a mercury ore furnace;

Figure 2 is a view in elevation taken along line 2--2 yof Figure 1; Figure 3 is a view of an ore ltravel deck taken line 3-3 of Figure 1;.'Y Y

along chamber;

Figure 8 isa partial view in detail of the ore outlet means taken along line 8 8 of Figure 1; A

Figure 9 is a partial view taken 'along line 9-'-9 of Figure 2; and v Figure lO'is a partially diagrammatic view pshowing the roperation of the ore charging means at various operational stages'of thefurnace.Y

lReferring now to the drawingsthe present invention lwillbe described in connection with a presently preferred embodimentY of a furnaceused in the 'V extraction of mercury from Vcinnabar. It is to be understood, how- Jever, that a .furnace in accordance with this invention maybe used for the extraction of othervolatile materials from ore or shale, such as, for example, the extractionloi' oilfrorn oil shale, and may also be used for such Y Stantially rectangular` in cross-section-A and. isV formed of any Suitable. material,l such as high temperature resistant stoele Any means; 4kno-.wn to.` the art may be. used to join the end plates 21 and 22, the sideplaie 2.3 and.` 2.4, and the-top.. and. bottom plates 25. and 26 respectively,y so long Yas' alL joints are substantially gas, tight to maintain/the shell, substantially hcrmetically sealed. The. shell 2t? 1s rnollrltcdv for oscillatory movement by means of, shafts 28 and 29 which are affixed to, the first endplate. 2.1. and they second end plate, 22V respectively substantially on the longitudinal, centerline. of thel shell. The shafts are mounted. in rotary bearings, 31 32. which are in. turn slidably. mounted in. brackets 33 and. 34 for somev vertical movement as shown. in Figure 6. That is, the. bearings are.A mountedY in vertical grooves inthe brackets 33 and 3.4 to allow some vertical movementof the shafts 28. and 29 duei to expansion and; contraction of the shell when it is heated or cooled. The brackets. 33 and` 34 are an integral. part of, or are alixedto, support arms 35, which are in turn. aiilxed to a. suitable base 36,01. the door to maintain the shell at. the, proper height above.. the base. The shell. is, also suppnrtcd. at the end. plates. thereof. by idler Wheels '3.17. and 381 which, are mounted for. rotating movement by means of rncnmtingJ brackets il and 42. affixed to the-baseI 36. The idlers define a peripheral groove in which arcuate support members. 43.' and 44 respectively are mateable. The arcuate support members are concentric in configuration to the longitudinal centerline through the shafts 28. and 29 such that the shell is supported ony the idlers by the arcuate members throughout oscillatory travel of the shell.

A- bearing rod '46 and 47 is affixed to each end plate for connection of a driving-arm 48 and 49, and the driving arms are in turn connected to aV crank `Sii which is supported and mounted from the base 36 for rotary movement, Suitable gearing and connections are made to a prime mover, not shown, by means WellA known to the art to drive the crank 511i through a full. circular driving movement as shown. Although driving arms are shown connected to each end of the shell for purposes. of sym.- metry, only one is essential and the means for connecting and driving the shell throughv an oscillatory movement are not critical and may be performed -by anyl one of many means known to the art. In addition, it is not essential that the center of oscillation of the shell be onthelongitudinal centerline of the shell, `although it is preferable that the. shell be mounted and driven such that it oscillates equally to both sides of the vertical plane as will become moreI apparent hereinafter. The angle through which the shell oscillates with respect to the vertical may be varied by adjusting the radius through which the driving arm 48, -is rotated by the crank 50, and accordingly adjusting thelength of the travel arm. The prime mover may be varied in speedtovary the speed of oscillation of the shell.

Within the shell 20 a plurality of ore carrying inclined decks.. are positioned. The decks 52 extend across the width and length of the shell and are a'ixed at the sides and ends of the shell. Thedecks are alternately inclined longitudinally with respect Ato the horizontal by an angle which is less than that at which the oreV will slide due to its own weight. That is, the rst deck 53 is inclined downward from left to right in the figures by an angle of two degrees with the horizontal, for example. The second' deck 54 is also inclined at the same angle, butl is inclined downward from right to left, while the third deck 55;,isV substantially parallel to the firstv deck 53 and is inclinedi downwardfrom left to right at two degrees. Thus, thev decks 52 are. alternatelyV inclined longitudinally, but

41 are not inclined transversely. At the lowermost end of the first and second decks an ore opening S7 and a fumes and heat opening 58 are provided as' shown in Figures l, 3, 4 and 7. The ore opening is positioned at one lower corner of the deck and is of suitcient size that ore may drop freely therethrough to the next lower` deck. Thus, ore will progress as more fully described hereinafter to the lower end-'olir the'rst deck 53 and thence through the ore opening 5,7; to the upper-end of the second deck 54. The openings 58 allow the passage of volatile constituentsV upward'vpast-I successive decks and also allow the free circulation of-.heatupward within the chamber. From the lower end of thesecond deck the ore will drop to thev third. deck.. Although three decks are shown in the presently preferred embodiment any number may be used dependent upon the length of passage through the furnace which is required in any given application of the. present invention. A4 fumes and heat opening is. provided through each deck as, shown in the figures. In this, embodiment. the. opening .58 is .positioned at the lower corner of the deck opposite, to the ore opening 57. In order to prevent o refrom dropping through the opening 58, a side wall.l orV shield 59. is aixed to the deck to block, the movement of ore to the. opening 53, thereby requiring the ore toy travel,- the tortuouspath and maintainingfree. openingsv for the. travel of-volatile consttuents., The heiglnof theshi-.eld issubstantially greater than., the, thickness of. oremovingalong the. deck` but is lowenough not.. to. interfere-with.. the circulation. of heat andV fumes.. as. describedhereinafter. y t Y The lowermost. deck, referringv particularly to Figures l, 5 and 7, which is fthe. third deck` 5.5. inthisembodiment, is. c oextensive withan ore outlet from the. shell. That is, a` heat opening 59 isprovided at each of the lower corners of the third deck and. shieldsv 60 are affixed at the edge of the. openings 59,-to prevent entry` of ore Ythrough the openings and to guide the ore to, the-core outlet opening 61 through the end plate. 22 of the shell 20. Aiixed tot the end plate 22 surrounding the-ore outlet opening 6l is. an ore outlet. chute 62 having a bottom. plate 63 which is coextensive with,- and continues the slopeof the third deck 55 to provide1 an uninterrupted travel` surface for the ore. The outletjchute 62 isclosed and substantially gasfigh, and; is axedto: the shellbyy means well kno-wn to the 'art to providev substantiallyy gas-tight joints. At the outer endl of the ore outlet'. chute-62 a. substantially verticaltube. 6.5;. is.provided.inullintriuptedcommunication withthe chute 62;l to continue@ closediore: passage from thefchute; as shown; int Figures. .1' and 8.'. A. transparent plate 66 is inserted in the Lube; at theiupper' end thereof to furnish a view port. An air or gas inlet; valve 6 .71-is axed to ythe-tuber 6j5 apprnximaterthe upper end thereof tol furnish aV means for irrtroducirig. a'. controlledA quantity of; air. or. gas to the shell. lnadditiom the inlet valve; 67 can be utilizedyto.- furnish; auxiliary.; fuelsuch as butano, for example, to the chamber. The valve is; of the type wellv known. to the artand. is of sufficient size'. to furnish the required volume.k off airI ow forzany given application. Suitable littings. can bei aixed tothe valve forV the connectionof aclosedgas'line. y

At the lower end of the ore outlet tube acontrolled outlet means releases. ore fromthe ftube at a controlled rate such'that someore remains` in thetube behind, the

outlet for a considerable verticalfdistance.V In the pres- Y ently preferredfembodjment'ore; or4 oretailings, is restrained inthe ytube 65.for a predetermined distance, but allowedftoescape'thereirom 'oya spring-loaded plate 79 which is mounted' a short distance beneathv the openv end of the tube. The plate 70 Vhas side walls extending upward adjacent two opposedfjsides of the. tube 65 and is open at the othertwo-sides;` The openl sides of the plate are those whichV are parallelwto the direction of oscillation of Lthe tube 651and' shell 20. That is, in ythis embodiment, the plate has a U-shaped cross-section with the sidesof the Uf positioned adjacent the walls of the tube vthe shell.

,ward to the tube 75.

' gaseosos the base of .the U positioned a substantial distance beneath the open endpof they tube. The plate is spring mounted and is supported by a plurality of springs 71 in compression which are in turn mounted upon an adjustable platform 72. The platform 72kis adjustably xed to the tube 65 beneath the plate 70 by means of support bolts 73 which are threadably connected to the tube 65 through bracket 74 such that the distance at which the platform is positioned beneath thek plate can be varied to vary Ithe spring pressure urging the plate toward the open end of the tube 65. Thus, it may be seen that yore, or ore tailings in the tube 65 will escape from the openrsides of the plate 70, but that the upward force of the plate will restrain the iiow of ore sufficiently to cause arsubstantial quantity of ore to be retained in the tube. As

the shell and tube os'cillate, the Weight of ore acting to compress the springs 71 will vary to agitatethe ore within the tube. Thus, the plate 70 allows escapel of ore residue from the tube while maintaining ore residue in the tube to a predeterminedheightrto prevent the ingress of air through the tube as discussed more fully hereinafter.

At the top of the shell 20 an ore charging means is provided to allow the charging of ore to the shell While vpreventing the ingress of air to the shell. Referring particularly vto Figures 1, 2 and 10, the ore charging means includes an ore inlet tube 75 which extends through the top plate 25 of the shell 20 in substantially gas-'tight contact therewith. The ore inlet tube is positioned approximate the upper end of the first deck 53 to deposit ore thereon. The ore inlet tube 75 has an open lower end and extends into the interior of the shell, i.e., to a substantial distance beneath the top plate 25. Positioned a short distance beneath the open end of the tube 75 isV an ore inlet plate 76 which Ais adjustably affixed to the a top plate 25 by means of bolts 7,7` which arethr'eadably connected to the top plate to vary the distance of the ore inletv plate 76 Vbeneath the open end of the tube 75.

The ore plate in this' embodiment is again substantially U-shaped in configuration with the sides of the U p0- sitioned adjacent the sides of the rectangular inlet tube `which would allow ingress of air or escape of gas or volatile constituents of the ore which are driven oi. The upper end of the ore inlet tube is coextensive with branches 78 and 79 respectively which are connected with the inlet tube 75 and disposed to opposite sides of the center line of the tube at an angley substantially equal to or greater than the maximum angle of oscillation of The ore passage branches 78, 79 are connected with an arcuate trough 80 at opposite ends thereof. Thus, in this embodiment the ore inlet trough 80 has a radius of curvature which is substantially symmetrical with the centerof oscillation of the shell 2.0, and the ends of the trough connect with branches 78 and 79 which in turn are joined at the ore inlet tube 75.

Thus, referring particularly to Figure 10, it may be seen that at or near one extreme of oscillation of the shell 20 and the attached charging trough 80, the sleeve 182 will be in register With a branch 78 and ore may ow from the hopper to the branch 78 and thus down- During the oscillatory cycle the bottom plate of the arcuate trough 80 passes beneath the sleeve 82 in sliding contact therewith and prevents ow of ore 4toward the ore inlet tube 75, until registration with .the other branch 79 isobtained at or near the opposite extreme of oscillation.v The divided position of the branches 78 and 79 with respect to the oscillatory cycle prevents overow of ore from the branchesV or the buildup which are perpendicular tothe direction of motion, and

j material is prevented as discussedhereinafter in conuection with the description of operation'.

shown in Figures 2 and 9, an impact means is provided at the orenlet which comprises a ball 84 confined within a track 87- formed of rods lextending between theY branches 78 and 79. The ball is free to travel between thebranches and will strike each branch in turn during oscillation to knock loose any ore which is stuck Withinthe branch, particularly after a shutfdownhasV allowed `the ore to settle. Since the impact means will not generally be in use a stop 90 is axed to the track Lof ore ahead of the sleeve 82. Flow of ore is thus conis heat insulated from :the shell walls. Means are pro- Y videdfor preventingdust or residuewithinthe shell from accumulating upon the heating element, by means ,of

shields`69, which extend downward past thesides of the heating elementsrfrom `the lower deck ,55, `The heatingv unit is supplied with current through a conductor cable 86. d Transparent viewports, such'as the vglassportv 83 are provided at appropriate locations in the walls of the shell in order to view the progress and condition of the ore. Thermometer wells are also located at various locations to indicate furnace temperatures at such locations. 1

A conductor tube 88 for the removal of volatile or gaseous constituents driven from the ore vis vconnected at the top-plate V25 of theshell 20.` Means for condensing the'lvolatile constituents, or gases, are Yprovided in thisV embodiment by a counter ow cooling jacket .89

which surrounds the conductor tube 88 from 4a position proximate thevgas outlet for a distance suicient to cool the -gases to condensation. The conductor tube 88 is preferably slightly 'sloped in the direction of new to fa-V cilitate ow of the condensateby gravity, and extends f tor-a swivel joint 91.0f the type `well known to the art which is substantiallyin alignment with the longitudinal axis of oscillation of the furnace., From the swivel joint :91 theconductortube 88 is stationary and extends to outlet end ofv the.r conductor tube is sealed from the atmosphere as,V for example, kby positioning the end of the tube 88 beneath the surface of water. A coolant inlet rline 92 extendsV from a swivel joint 93 and is connected proximate the end of the' cooling'jacket 89. A coolant Youtlet line 94 is connected tothe cooling jacket proxi- "mate the conductor 88 outlet connection to the shell k20 and extends to a swivel joint 95 which is again substantially valigned with the longitudinal axis of oscillation of the shell. 'For various treatments of oresY or in other applications of a furnace in accordance with this invention, it is desirable to control the pressure within the shell. That is, in'some instances it is desirable to vheat the contents of the furnace under sub-atmospheric conditions while at other times a slightly pressurized condition is necessary. Means can therefore beprovided at the conductor tube 88 for restricting the outward flow of the volatile constituents to create pressure within the shell 20, or to speed the ow in order to create a slightly sub-atmospheric condition in the furnace is desirable to `facilitate volatilization of the mercury. Accordingly, the conductor tube 88 extends beyond the swivel joint 91 to a closedktank` 96 containing water which partially fills the tanlk to a level above the open end of the conductor tube 88. A vacuum pump 97 is connected into the'tank above the water level to maintain the tank'at a partial vacuum. Thus, the condensed constituents ow from the conductor tube 88 and into the water and a partial vac'- uum is maintained in the conductor tube 88 and shell 20,

apanage In operation, referring now to Figures 1 and 2, the heat of the furnace is raised. to the required internal temperature by means of the heatingunit 35 and the furnace is set in oscillation about the longitudinal axis extending through the shafts 28 and 29. Since the furnace shell. 20 is also supported on the idlers 37 and 38 the weight of the furnace and its contents are not carried by the bearings 31 and 32 alone. Vertical movement of the bearings acts to compensate for expansion and contraction of the shell and maintains distribution of the weight among the four support points. Oscillation of the furnace is imparted by the prime mover through the crank 50 andV driving rods 48 and 49. The rate of oscillation may be varied by varying the speed of the prime mover while the angle of oscillation may be varied by varying the radial location of the driving arm or arms upon the crank. When the -furnace is set in oscillation the shell 20 and all parts appurtenant thereto'are set in motion.v That is, the ore outlet `chute 62; the ore inlet tube, branches and arcuate trough; and the conductor tube 88, coolant jacket 89, and coolantA inlet and outlet lines 92 and 94 will oscillate. Y

`Ore is then fed tothe stationary hopper 3i and fills the sleeve 82. Referring now to Figures 2 and l0, when the furnace approaches the extreme position of oscillation to the right side of the vertical for example, the branch 73 in Figures 2 and l0 will be in registration with the sleeve 82. Ore will then ow through the branch 78 to the ore inlet tube 75 by gravity. As the direction of oscillation reverses the sleeve 82 will vbe closed by the bottom'plate of the arcuate trough 80 with which it is in sliding contact. As the opposite extreme of oscillation isapproached the sleeve 82 moves into register with the second branch 7 'and ore flows from the Vhopper Si throughthe second branch 79 and to the ore inlet tube 75. In `this position the first branch 78 is approximately horizontal. Thus, while one branch 79 is being partially emptied by liowof ore therefrom and being relled from the sleeve 32, the opposite branch 73 is approximately horizontal and little or no ow ofl ore* occurs through thel opposite branch 7S.

Raising or lowering of the ore plate 75 by means of the adjusting bolts 77 increases or retards the ilow of ore from the ore inlet tube 75. That is, lateral openings are provided between the ore plate 76 and the open end of the ore inlet tube 75. As the ore inlet tube oscillates to one side of the vertical, the ore ows from the ore inlet tube and aroundV the sides ofthe ore plate at the downward end of each side. Conversely, during oscillation of the furnace to .the opposite side of the vertical, ore is allowed to ow from the opposite lateral opening of the ore plate.. By raising or lowering the ore plate 76 with respect to the end oi the inlet tube 75 the size of the lateral. openings is varied to a position at which the rate oiilow of ore from `the iniet tube is such that ore is continually present in the inlet tube and both branches 78 and 79. The presence of .the ore supplies a sealing means which prevents `the ingress of vair to the furnace and preventsV the escape of gases and fumes from the furnace.

Thus,.the ore is deposited at a controlled rate upon the iirst ore carrying deck 53 proximate the uppermost end thereof. As discussed hereinbefore, the longitudinal slope of the deck is insutlicient to cause a sliding of the ore, however, as the deck oscillates the ore will slide transversely due to the oscillation with a. longitudinal component due to the siepe. Thus,` the ore will follow a tortuous zig-zag path. down the first deck 53 to the ore opening S7 at thelowermost end of the deck 53. The ore then drops onto the second deck 54 and travels in a similarly tortuous path in the opposite direction to the ore opening 57 of vthe .second deck and then to 7thethird deck .55. fst-tbe third deck the=ovre1follows the :tortuous Path i the lower 'rend of the vdesk ssY and 'out ef; the' sten 2G intothe closedoutlet chute 621.y

During-"the slow flow of ore long this ytortuous passage the ore is agitated and 'heating causing its volatile constituent, which is mercury YihV this illustrative embodiment, to be driven oli and to ow to they outlet conductor tube 88. The heating of the ore is accomplished by the heating unit 35 and the circulation of heat is accomplished'by circulation through the openings 58A in each deck. Similarly, the escape of volatile constituents from each `deck as the ore progresses is accomplished by the iiow of the fumes through the openings 58 to the upper plate of the shell.l The volatile constituents then escape into the conductor tube 88.

Thus, the ore being treated is subjected to a series of agitated movements in a thin layer to obtain maximum heating and extraction'eiciency while still maintaining 'a compactfurnace That is, the ore is constantly Shifting,

rolling, turning and changing position to absorb all heat possible during its movement. Since the absorption of heat is eiiicient, the heat supplied to the furnace is substantially completely extracted by the heat of vaporization imparted tothe ore before the heated fumes Vand vaporized gases reach the conductor tube 88. Therefore, the heat supplied to therfumacev need only be sufficient to maintain the Vvolatile constituents in a vaporizedrcondition as they enter the conductor tube 38. Accordingly, the cooling system required to condense the volatile constituents is tess than that required by prior art devices since hot exhaust fumes and gases are substantially eliminated.

The ore` or ore residue which has reached the ore outlet chute o2 iiows downward therethrough and is restrained by the ore outlet plate as discussed hereinbefore. That is, the compressive force of the springs 71 is adjusted by means of the bolts 73 such that the ore is allowed to escape through the open sides of the plate at a rate which maintains ore in the outlet chute 62 at all times. As .the ore outlet chute 62 oscillates ore tailings in excess of those retained in the chute for sealing off the chute 62 to the atmosphere escape from'rst one side .and then the other side of the ore outlet plate 7 0, but at all times the chute is iilled with ore to prevent the ingress of air to the shell or the escape of gases therefrom. As previously described the controlled entry of air or other gases may be provided through the valve 67.

As the volatile material passes through the conductor tube. 88 it passes through 'the heat exchanger or cooling jacket S9 and is condensed to be recovered beyond the swivel. joint 91 -in liquid form. The maintenance of a slightly sub-atmospheric pressure at the conductor tube outlet will aid in the extraction of the gaseous constituents from the shell and will facilitate volatilization in the case of vmercury extraction. As discussed hereinbefore, in this embodiment recovery of the mercury is achieved by exhausting the mercury which has been condensed in the tube into a quantity of water, the surface of which is maintained under a slight vacuum.

The cooling water is admitted to the cooling jacket 89 through the coolant inlet line 92 and out of the jacket through the outlet line 94.

Various modiiications of the apparatus of the present invention, its arrangement of parts, and mode of operation will be apparent to one skilled -in the art in view of the foregoing description. For example, in order to obtain maximum economy of space, when space is a consideration, the heating unit may be positioned between the lowermost deck and the deck above with suitable shielding to protect the elements from settling'dust. That is,l between.V the second and third decks in this embodiment. In such an arrangement it is preferable that the heat and'fume openings 58 be positioned in the yfirst and second decks substantially along the centerline of the shell at oppositeends of therdecks and closed tothe passage-of ore by.' shields on. all. sides Similarly, with the openings 58 relocated, it is preferable for some applications to provide an ore opening 57 at both of the lower corners of each ore carrying deck above the lowermost deck. In an alternative embodiment of the present invention the shell and decks are of greater width than length to allow a greater movement of the ore in the direction of oscillation, and, in addition, the ore outlet chute is located to the side of the lowermost deck proximate the lower end of the deck, rather'than on the longitudinal centerline as in the presently preferred embodiment. Further, similar modifications and uses of the present invention are possible within the scope of the invention.

Thus, the present invention provides an ore roasting furnace in which maximum heating eliiciency is achieved in a substantially controlled atmosphere. A continuous regulated ow and agitation of ore through the furnace is possible without the ingress of air or escape of gaseous constituents from the furnace. The rate of flow of ore through the furnace is variable and may be closely controlled and predetermined for any particular application by use of the ore charging and outlet means of the present invention. In addition, the furnace contains a minimum of moving parts and parts subject to wear or abrasion With no moving parts within the heated chamber for maximum life and economy.

What is claimed is:

l. An ore roasting furnace for extracting the volatile constituents from ore comprising: a shell defining a heated ore chamber; means for heating said chamber; a plurality of ore carrying decks within said chamber and aflixed thereto in stationary relationship, said decks being alternately longitudinally inclined to a first predetermined angle with respect to the horizontal axis of said shell, said predetermined angle being less than the angle at which said ore will move under the force of gravity; means for oscillating said shell to a second predetermined angle -to each side of the vertical axis of said shell in the direction substantially transverse to said longitudinal direction, said second predetermined angle being greater than the angle at which said ore will move under the force of gravity; a hopper for feeding ore to said chamber, ore inlet means proximate the upper end of the uppermost of said decks, said ore inlet means'including a 4tubular inlet to said chamber having an open end extending into the interior of said chamber, first and second divided inlet branches communicating with said tubular inlet exteriorly of said chamber in the plane of oscillation of said chamber, an arcuate trough connected between said divided branches, an ore outlet from said hopper extending into said trough and being closed thereby, said hopper ore outlet and said branches being alternately in registration at the limits of oscillation of said chamber, means for restraining the ow of ore through said tubular inlet so as to keep the inlet partially iilled with ore to prevent the ingress of air to'said chamber; ore outlet means proximate the'lower end of the lowermost of said decks, means in combination with said ore outlet means to prevent the ingress of air to said chamber; ore openings through each of said decks above said lowermost deck proximate the lower end thereof; and outlet means from said chamber for said volatile constituents.

2. An ore roasting furnace forv extracting the volatile constituents from ore comprising: a shell dening a heated ore chamber; means for heating said chamber; a plurality of ore carrying decks within said chamber and aixed thereto in stationary relationship, said decks being alternately longitudinally inclined to a rst predetermined angle with respect to the horizontal axis of said shell, said predetermined angle being less than the angle at which said ore will move under the force of gravity; means for oscillating said shell to a second predetermined angle to each side of the vertical axis of said shell in the direction substantially transverse to said longitudinal direction, said second predetermined angle being greater than the angle at which said ore will move under the force of gravity; a hopper for feeding ore to said chamber, ore inlet means proximate the upper end of the uppermost of said decks, said ore inlet -means including a tubular inlet to said chamber having an open end extending into the interior of said chamber, lirst and secondy divided inlet branches communicating with said tubular inlet exteriorly of said chamber in the plane of oscillation of said chamber, an arcuate trough connected between said divided branches, an ore outlet from said hopper extending into said trough and being closed thereby, said hopper ore outvlet and said branches being alternately in registration at the limits of oscillation of said chamber, means for restraining the flow of ore through said tubular inlet so as to keep the inlet partially tilled with ore to prevent the ingress of air to said chamber; ore outlet means proximate the lower end of the lowermost of said decks, said ore outlet means including a tubular outlet communicating with the lowermost end of the lowermost ore carrying deck and extending to the exterior of said chamber for Ioscillation therewith, a resiliently mounted plate spaced beneath the outer open end of said tubular outlet, said plate being mounted such that a quantity of ore is maintained in said tubular outlet; ore openings through each of said decks above said lowermost deck proximate the lower end thereof; and outlet means from said chamber for said volatile constituents.

3. An ore roasting furnace for extracting the volatile constituents from ore comprising: a heated ore chamber, means for oscillating said chamber about the longitudinal `axis thereof, ore inlet means affixed to said chamber for oscillation therewith, said ore inlet means comprising a tubular .inlet to said chamber having an open end extending into said chamber at the top thereof, iirst and second divided inlet branches communicating with said tubular inlet in Y-coniiguration in the plane of oscillation of said chamber, an arcuate trough connected between said branches at the upper ends thereof, a stationary hopper for feeding ore to said ore inlet, a stationary ore outlet from said hopper extending into said trough and closed thereby, said ore outlet and `said open branches being alternately in registration at Ithe limits of oscillation of said chamber.

References Cited in the le of this patent UNITED STATES PATENTS 789,135 Baggaley May 9, 1905 1,535,467 Hedges l Apr. 28, 1925 1,611,098 Borner Dec. 14, 1926 1,863,686 Corsalli lune `21, 1932 2,061,698 Ewart Nov.f24, 1936 2,570,232 Hansgng Oct. 9, 1951 2,733,912 Newcomb et al. Feb. 7, 1956 

